Not referring to the XMTR Gain cal... talking about the Tune PWR cals... I have a decent dummy load I think... It's a Navy DA-412/U (50-Ohm, 600W continuous, 900 W for 15 minutes). It has no measurable reactance 0-30 MHz, and less than 2 Ohm up to 400MHz... at least according to the analyzer I had access to. Will likely get a precision 50-Ohm dummy load for cal purposes since it only needs to be 5 and 50 W for the cals...
I'm a bit OCD on certain things... like eliminating variables on basic cals so I don't have to worry about my end during ops. ______________________ Clay Autery, KG5LKV MONTAC Enterprises (318) 518-1389 On 4/26/2016 9:57 PM, Ron D'Eau Claire wrote: > For the Transmitter Gain calibration, all you need is a decent dummy load. > The LP-100A is not a dummy load. My 20-year old inexpensive MFJ dummy load > does a good job for that. (But note it has never been abused, such as > running power into it until it gets hot or smells.) A well designed dummy > load will have very little reactance from stray capacitance or inductance. > That leaves only the value of the resistive element, which you can check > with your DMM. It's the resistive element that is most susceptible to damage > from overheating it, just like any other resistor. > > For calibrating the wattmeter in your K3S beyond the factory setting, > whatever makes you happy is perfect. There is no operational or performance > advantage to "improving" the factory settings. The LP-100A claims 3% power > display accuracy which is much better than most (if the claims are true). > For example, the ARRL lab is quoted in their manual saying "They specify > their measurement error for power as +/- 5%, and for PEP power, +/- 8%." > Note the +/- meaning the power error may vary by 10% for constant carrier > and 16% PEP. Those are much more typical values for good, even lab quality > power measurement equipment. > > 73, Ron AC7AC > > -----Original Message----- > From: Elecraft [mailto:[email protected]] On Behalf Of Clay > Autery > Sent: Tuesday, April 26, 2016 6:50 PM > To: Elecraft Reflector > Subject: [Elecraft] Wattmeter for K3s Calibration > > Would the LP-100A meet the accuracy/precision requirements to do the power > cals outlined in the K3s Manual? > > If not, please supply recommendation for one that will do the job > adequately. > > Thanks! > > -- > ______________________ > Clay Autery, KG5LKV > MONTAC Enterprises > (318) 518-1389 > > ______________________________________________________________ > Elecraft mailing list > Home: http://mailman.qth.net/mailman/listinfo/elecraft > Help: http://mailman.qth.net/mmfaq.htm > Post: mailto:[email protected] > > This list hosted by: http://www.qsl.net > Please help support this email list: http://www.qsl.net/donate.html Message > delivered to [email protected] > ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[email protected] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to [email protected]
